Many electronic devices operate with direct current (DC). However, most electrical transmission and/or distribution systems provide alternating current (AC). Accordingly, many electronic devices utilize an AC-to-DC power adapter, variously referred to as an AC adapter, wall adapter, wall wart, or charger, to convert AC power from an AC supply (e.g., the mains electrical supply) to DC power that may be used to operate and/or charge the electronic device. Many power adapters consume standby power, that is, they consume power even though the electronic device may be disconnected, fully charged or turned off. Users routinely leave power adapters plugged in or otherwise connected to the AC supply. As a result, the widespread use of power adapters consumes a significant amount of standby power, which, in turn, provides little or no utility and effectively wastes electrical energy.